A cellular communications system typically has base stations distributed throughout an area to provide data connectivity throughout the area. The cellular system allows wireless communications to use less power and it allows frequencies to be reused by different subscribers connected to different base stations. Each base station connects through a communications infrastructure to a communications backbone to connect to other subscribers and to users and systems outside the cellular system.
A conventional base station is referred to as communicating within a cell or, sometimes, a macrocell of the cellular system. A macrocell may have a cross-section of several miles. To further extend a cellular system, microcells have been used to serve a smaller area. This is useful in extremely dense urban areas to allow frequencies to be reused within smaller areas. Microcells are also used to extend the range of a system beyond the reach of a base station at lower cost than a typical base station. To augment systems of macrocells, and microcells, nanocells, picocells, and femtocells are used, each corresponding to a smaller base station.
For WiMAX (a set of standards promulgated by the WiMAX forum), a femto cell is centered around a WiMAX Femto Access point (WFAP), a low-power WiMAX Base Station, operating in licensed band to connect to subscribers. It is intended to provide service for a limited number of concurrent users over small areas such as a home or a SOHO (small office, home office) environment. To connect to the cellular network it uses a shared broadband connection. This connection can be operated by a different service provider.
Ideally, the WFAP also supports some mobility for the subscriber and allows the subscriber to be handed over to a macrocell base station.